Closed-loop Supply Chain Research Articles

Balancing Stakeholder Interests in Sustainable Project Management: A Circular Economy Approach

Balancing stakeholder interests in sustainable project management presents a critical challenge, particularly when adopting a circular economy (CE) approach. This review explores the integration of circular economy principles such as reducing waste, reusing materials, and promoting recycling into project management while addressing the diverse and often competing interests of stakeholders. Sustainable project management aims to harmonize economic, environmental, and social objectives, making the alignment of stakeholder goals a complex yet essential task. Stakeholders, including investors, customers, regulators, local communities, and internal project teams, often have varying priorities, ranging from maximizing profitability to minimizing environmental impact and ensuring social responsibility. This study reviews key strategies for managing these competing interests through collaborative decision-making, transparency, and stakeholder engagement. Life Cycle Assessment (LCA), closed-loop supply chains, and sustainable procurement are examined as practical tools for integrating CE principles throughout the project lifecycle. Additionally, the review emphasizes the importance of education and communication in fostering stakeholder buy-in, enhancing long-term sustainability outcomes, and improving resource efficiency. Case studies from industries such as construction and renewable energy demonstrate how stakeholder collaboration in adopting CE practices leads to both environmental benefits and project success. The findings suggest that balancing stakeholder interests in a circular economy framework not only enhances sustainability but also drives innovation and competitiveness. This research underscores the need for continual engagement and adaptive strategies in project management, ensuring that stakeholder alignment with circular economy goals results in more resilient and sustainable project outcomes. Ultimately, adopting a circular economy approach within project management offers a viable pathway to achieving long-term sustainability and creating shared value among stakeholders.

Logistics supply of the eco-industrial parks’ residents

This paper provides a comprehensive analysis of the logistics supply for residents of eco-industrial parks and examines its influence on the competitiveness and sustainability of these parks. Eco-industrial parks, as integral components of circular economy systems, facilitate the efficient use of resources, reduction of environmental impact, and optimization of supply chain operations. The purpose of the paper is to assess the logistics systems within eco-industrial parks, identify the challenges and opportunities for enhancing operational efficiency, and explore how these strategies can be adapted to the Ukrainian context, particularly during the ongoing war. The research draws upon international case studies, focusing on the integration of advanced technologies and green logistics practices in China, Europe, and other regions. The methodology used in this paper combines inductive analysis of literature, comparative analysis, and empirical research based on existing models of logistics management within EIPs. A key part of the analysis involves the evaluation of institutional pressures and their role in promoting sustainable supply chain management. The paper examines how these practices, when applied in a coordinated and efficient manner, help to reduce costs and carbon emissions, while also improving resource-sharing between companies located within eco-industrial parks. The results show that implementing circular supply chain management significantly enhances the performance of companies operating within EIPs. Firms that adopt renewable energy sources and optimize their transportation systems using electric vehicles report a 13-14% reduction in operational costs and carbon emissions. The integration of technologies such as Geographic Information Systems and Multi-Criteria Decision-Making tools has also proven beneficial in the site selection and planning of eco-industrial parks, allowing for the optimization of logistics and resource allocation. In Ukraine, which is currently facing critical challenges due to war, adopting these strategies can strengthen industrial clusters, reduce dependence on external resources, and enhance resilience against economic shocks. The scientific novelty of this research lies in the proposed structure of the logistics supply for eco-industrial parks’ residents. The practical implications of this paper include the application of green logistics technologies, the development of self-sustaining energy networks, and the implementation of closed-loop supply chains that promote resource efficiency. Future research directions should focus on the development of logistics optimization models for Ukrainian eco-industrial parks, particularly in war-torn areas, and the assessment of their long-term economic and environmental impact. Additionally, the paper advocates for the expanded use of renewable energy sources and Geographic Information Systems-based planning tools to further improve logistics processes and reduce the ecological footprint of industrial activities. The results of this paper underscore the importance of inter-firm cooperation and the strategic use of logistics to foster both economic and environmental resilience in eco-industrial settings.

Power battery modular innovation investment strategies with government subsidy policies

This paper investigates the closed-loop supply chain decisions of battery manufacturers considering innovation investments and different subsidy methods provided by the government. The analysis encompasses four scenarios: whether battery manufacturers engage in innovation investments and whether the government opts for technology R&D subsidies or production subsidies. The study finds that innovation investments by battery manufacturers can enhance the modularization level of batteries. The reward or penalty measures for recycling quality imposed on automobile manufacturers elevate the quality of battery recycling, and also increase the wholesale price of batteries and the retail price of automobiles. After implementing R&D and production subsidies, both the modularization level of batteries and the profits of supply chain members exceed those without subsidies, though these subsidies do not affect the quality of battery recycling. R&D subsidies more effectively promote innovation capacity and product quality among battery manufacturers, whereas production subsidies more significantly boost the profits of both battery manufacturers and automobile manufacturers. Therefore, subsidy measures should be tailored according to different stages of the power battery industry's development. Regardless of whether battery manufacturers invest in innovation or whether the government provides subsidies, collaboration between battery manufacturers and automobile manufacturers is essential to coordinate the closed-loop supply chain. The research findings offer valuable guidance for formulating subsidy policies in the new energy vehicle industry across different periods, and also provide theoretical insights for decision-making behaviors among related enterprises.

Decision making and benefit analysis of closed-loop remanufacturing supply chain considering government subsidies

Remanufacturing closed-loop supply chain can effectively deal with the deterioration of environmental resources and the limited supply of resources as a part of circular economy. Government subsidies are an important factor to promote its development. In this paper, we consider a two-stage remanufacturing closed-loop supply chain, where the retailer is responsible for recycling, and the manufacturer will innovate in remanufacturing technology based on the extended producer responsibility system. The study constructs a Stackelberg game model with the manufacturer as a leader, and compares the different impacts of the two subsidy strategies on supply chain decisions (i.e., subsidies for investment in remanufacturing technology innovation and subsidies for the cost of remanufactured products). Numerical analyses are conducted to visualize the effects of subsidies on the decision-making of closed-loop supply chain members, environmental benefits, and social welfare. The findings indicate that when the level of subsidy is low, government subsidies for investment in remanufacturing technology innovation can accelerate the upgrading of remanufacturing technology, leading to higher environmental benefits and social welfare compared to subsidising the cost of remanufactured products. The results show that when the level of subsidy is high, government subsidies for remanufactured product costs, while yielding greater environmental benefits and social welfare compared to subsidies for investment in remanufacturing technology innovation, have a lesser impact on the advancement of remanufacturing technology.

Rare earth recycling and remanufacturing: Impacts on oligopoly markets and industry development from a closed-loop supply chain perspective

The recycling of rare earth elements (REEs) yielded a dual benefit by alleviating supply constraints and contributing to environmental preservation. Independent recyclers (IRs), upon extracting REEs from waste materials, not only supplied the recovered REEs to the REE conglomerates but also engaged in competitive relationships by remanufacturing REE products. This study established a closed-loop supply framework, allowing the IR flexibly to choose between remanufacturing or direct sales strategies. Using the Cournot model under inequation constraints and real market data, to explores the impact of REE acquisition prices and recycling technologies on the closed-loop supply chain (CLSC) and society. The results indicated that: (1) The recycling mode and technology do not affect market share. Compared to the IR, REE conglomerate exhibit significant monopolistic advantages, occupying at least 85.1% of the market share, which can increase to a maximum of 98% as acquisition prices rise. (2) The acquisition price of recycled REE has an “inverse U-shaped” relationship with the profits of REE conglomerate and a positive relationship with the profits of IR. (3) The recovery rate is negatively related to the profits of REE conglomerate and positively related to the profits of IR. Increasing the REE recovery rate will enhance the profitability of the IR. (4) In terms of social effects, higher acquisition price of recycled REE continuously reduce consumer surplus and social welfare. Although the REE recovery rate does not affect consumer surplus, it has a significant positive impact on social welfare.

Closed-loop supply chain decision making and coordination considering channel power structure and information symmetry

China is currently undergoing a phase of high-quality development, with increasing emphasis on the circular economy, energy conservation, and environmental protection by both the government and enterprises. This paper examines a secondary supply chain comprising manufacturers and retailers, focusing on three supply chain decision-making models: one where the manufacturer is the channel leader, one where the retailer is the channel leader, and one where both parties have equal power. The study investigates the impact of manufacturers misrepresenting their Corporate Social Responsibility (CSR) information and the challenges associated with recycling efforts on the optimal performance of the supply chain. The findings reveal that when manufacturers lead the supply chain, they do not misrepresent their private information. However, when retailers dominate, manufacturers tend to underreport their CSR levels and the difficulty of recycling efforts. In scenarios where manufacturers and retailers have equal power, manufacturers do not misreport the difficulty of recycling but do underreport their CSR levels. This misreporting benefits the manufacturers at the expense of retailers and overall supply chain profitability, while also discouraging the recycling of used products. Across all three power structures, the study shows that retailers’ marketing efforts decrease as the misrepresentation of recycling difficulty increases, and increase as the misrepresentation of CSR levels increases. To mitigate the effects of manufacturers’ misreporting under information asymmetry, the paper proposes revenue-sharing contracts and two-part pricing contracts to coordinate the closed-loop supply chain under different power structures. Both contracts are shown to achieve Pareto improvements within the supply chain. This research provides valuable insights for enterprises operating within closed-loop supply chains, highlighting the importance of enhancing communication and cooperation to bridge information gaps and ensuring the coordina.

Towards a Closed-Loop Supply Chain: Assessing Current Practices in Empty Pesticide Container Management in Indonesia

Pesticides are essential to modern agriculture, significantly enhancing crop yields and quality to ensure global food security. Their critical role in preventing hunger is highlighted by the notable increase in global pesticide trade over the past decade. In Indonesia, pesticide usage has surged, with a 24% rise in registered pesticide formulations between 2017 and 2021. However, this increase presents challenges, particularly in the disposal of empty pesticide containers (EPC), which pose substantial environmental and health risks if improperly managed. To address this, a closed-loop supply chain (CLSC) is proposed as an effective, eco-friendly solution for the management of EPC waste. This study evaluates the implementation of a CLSC for EPC in Indonesia, employing rich picture analysis and stakeholder interviews to identify key challenges, opportunities, and strengths. Notable challenges include regulatory gaps, financial and operational feasibility, and limited farmer engagement. However, opportunities exist in enhancing environmental sustainability, generating economic benefits, and gaining support from industry groups. One key strength is the widespread practice of triple rinsing among farmers, with 62.63% of respondents already adopting this method. This study underscores the important of establishing clear and enforceable regulations, introducing financial incentives and supportive policies, promoting public–private partnerships, creating targeted behavior change interventions, and ensuring organizational commitments and training programs. These insights are crucial in developing a sustainable CLSC, ensuring both environmental and economic benefits.

A distribution-free-based approach for stochastic food closed-loop supply chain

ABSTRACT Resource scarcity has driven growing interest in circular economy (CE). Closed-loop supply chain (CLSC) with returnable transport items (RTIs) in the food industry is an important component of CE. However, existing works on food CLSC with RTIs have not simultaneously considered the perishability, facility location, and uncertain demand under limited information. Therefore, this work addresses a new food CLSC optimisation problem. We first propose a non-linear chance-constrained programming model. It is then transformed into a mixed-integer linear programming model via using the distribution-free (DF) method and sample average approximation (SAA) method, respectively. An illustrative example reveals that the DF method needs only 10.50% of the computation time of the SAA method. To address large-scale problems, an improved Lagrangian relaxation (LR) method is developed. To address the computational challenge in large-scale problems, an improved Lagrangian relaxation (LR) algorithm is developed. Results show that CPLEX achieves a gap of 75.57%, while the LR surpasses it by finding near-optimal solutions with a gap of 1.22%, using only 31.82% of the computation time required by CPLEX. For this work, the main insights are summarised: (1) extending product shelf life can reduce the total cost; and (2) to alleviate uncertain demand and production risks, production capacity and product inventory capacity can be appropriately expanded, but excessive investment may not improve returns.

Integrating risk management in implementing circular economy principles in the healthcare sector: a case study from Indonesia

Purpose The purpose of this study is to explore the integration of risk management and circular economy (CE) principles within the healthcare sector to promote sustainability and resilience. Specifically, the study aims to demonstrate how risk management can support the transition to a circular economy in healthcare supply chains. By integrating risk management practices with CE principles, healthcare organizations can identify potential risks and opportunities associated with circular initiatives. Design/methodology/approach This study adopts a qualitative research approach, using a case study methodology with semi-structured interviews conducted at primary care facilities to understand the application of CE principles in practice. The study uses fuzzy logic methods to assess and mitigate risks associated with strategies promoting CE principles. Additionally, key performance indicators are identified to evaluate the effectiveness and enhance the resilience of these strategies within healthcare supply chains. Findings The study highlights the critical role of robust risk management strategies in facilitating the transition to a circular economy within healthcare organizations. Primary care facilities, which are critical to frontline healthcare delivery, are particularly vulnerable to product shortages due to supply risks. This study focuses on critical protective equipment, specifically latex gloves and assesses operational risks, including supply, demand and environmental risks, using a fuzzy logic-based model. Import delays were found to be a moderate risk, typically occurring once a year. The research highlights critical KPIs for a successful CE transition within healthcare supply chains, such as on-time delivery and service quality, which are directly related to the risk of supply chain disruption. In addition, the study highlights the significant impact of other CE strategies on healthcare supply chains, including localized production and manufacturing, innovation in product development, reverse logistics, closed-loop supply chains and the adoption of lean principles. Practical implications This study provides valuable insights for healthcare organizations to optimize resource efficiency, reduce waste and promote circularity in their operations. By implementing the proposed solutions and focusing on the identified KPIs, organizations can develop strategies to achieve sustainability goals and enhance resilience in healthcare supply chains. Originality/value This study contributes to the literature by demonstrating the application of risk management in facilitating the transition to a circular economy in the healthcare sector. The use of fuzzy logic methodology offers a novel approach to assessing and mitigating risks associated with critical product failures in supply chain activities. The study’s findings provide practical guidance for healthcare organizations seeking to integrate circular economy principles and improve sustainability performance.

Decision-making in closed-loop supply chains: Effects of government subsidies and risk aversion

Closed-loop supply chains (CLSCs) play a crucial role in promoting sustainable resource management, yet their implementation faces challenges in balancing economic viability with environmental goals. While existing research has explored various aspects of CLSC operations, the interplay between government subsidies and risk-averse behavior of supply chain members remains understudied, particularly in systems involving third-party recyclers. This gap hinders the development of effective policies and management strategies for sustainable CLSCs. Herein, we employ a Stackelberg game-theoretic model to investigate decision-making processes in CLSCs under four distinct subsidy scenarios, incorporating risk aversion through mean-variance utility functions. Our results reveal that subsidy effectiveness significantly depends on remanufacturing costs and risk attitudes of supply chain participants. When remanufacturing costs are high, subsidizing third-party recyclers yields superior environmental and economic outcomes, whereas manufacturer subsidies prove more effective when these costs are low. Moreover, we identify critical thresholds in subsidy levels and risk aversion that alter decision-making patterns. These findings provide a framework for designing targeted subsidy policies and risk management strategies in CLSCs, advancing the field of sustainable supply chain management by offering nuanced insights into the complex dynamics between government interventions, risk preferences, and CLSC performance.

Pricing and collection decisions of a closed-loop supply chain with remanufacturing under reciprocal preferences

This paper examines the effects of reciprocal preferences on the performances of a closed-loop supply chains (CLSC) with remanufacturing. Specifically, we incorporate reciprocal preferences into a two-echelon CLSC in which the manufacturer collects used products and then remanufactures the other parts except for key components as well as producing new products, and must purchase such key components from the supplier. Using a supplier-led Stackelberg game framework, the models are constructed with and without reciprocity, and then the effects of reciprocity on channel efficiency, consumers, environment and society are examined. We show that, (i) if the supplier reciprocates, the collection rate, the CLSC’s total profit, the channel efficiency and the consumer surplus enhance. Additionally, if only the manufacturer reciprocates, the CLSC’s profit remains constant; (ii) under certain conditions, the reciprocal preferences of both channel members aggravate environmental impact, while benefit social welfare; (iii) Pareto improvement can be achieved if the reciprocity parameters of both channel members are relatively high, and a simple procurement price contract can conditionally coordinate the CLSC. Finally, two extensions are studied by considering consumer heterogeneity and solving a two-period game problem, and the results characterize how reciprocal behaviors drive the performances of channel members.

Adjustable robust optimization for integrated fleet sizing and vehicle routing problem with simultaneous delivery and pickup in closed-loop supply chain management

ABSTRACT The fleet sizing problem is a critical challenge in closed-loop supply chains because of the additional requirements of managing product returns. To tackle this challenge, this study addresses the integration of fleet sizing with vehicle routing problem in closed-loop supply chain management, considering simultaneous delivery and pickup under demand uncertainty. A mixed-integer linear programming model is proposed to minimize vehicle acquisition and shipment costs, and a multi-stage adjustable robust optimization formulation is employed to handle uncertainty. Prior studies have neglected to address this important problem due to a lack of efficient solving methods. Hence, three exact, heuristic, and metaheuristic algorithms are developed to solve the problem. The numerical experiments demonstrate that the proposed methods outperform the existing Hyper-box based Branch-and-Partition method, improving computational efficiency and solution quality. This study also helps practitioners make better fleet sizing decisions under uncertainty.

Configuration and optimisation of a green closed-loop supply chain with delivery time and green investment considering government subsidy under meta-heuristics algorithms

Consumers' environment consciousness, together with the fierce rivalries among companies, has attracted increasing attention from scholars and industries to the configuration and optimisation of green closed-loop supply chain. However, current studies of closed-loop supply chains rarely consider both the uncertainty from the market and the quality from the recycled used products. Therefore, this article constructs a green closed-loop supply chain total profit model that considers government subsidies, delivery times, green investment and the above uncertainties. Fuzzy chance constraint method is used to solve the uncertain demand; genetic and particle swarm optimisation algorithms are adopted to calculate the model. This study finds (1) enterprises can formulate flexible and adaptable strategies based on different demands; (2) their delivery time decisions rely on both consumer demand and their logistics development levels; (3) enterprises should adjust their delivery times and green investment decisions according to consumers' different sensitivities; (4) enterprises can increase profits by recycling products within a certain range of greenness; (5) for improving recycling and remanufacturing rates, the government can provide secondary subsidies to enterprises for product recycling within the green range of 0.35 ∼ 0.40. This study contributes to the optimisation of strategies developed by enterprises under conditions of subsidies and multiple uncertainties.

Study on the Selection of Recycling Strategies for the Echelon Utilization of Electric Vehicle Batteries under the Carbon Trading Policy

Global climate change has prompted all sectors of society to take urgent action to reduce carbon emissions. Electric vehicles are the key to low-carbon transportation transformation, but their popularity has led to difficulties in disposing of used batteries. Improper handling will pollute the environment and violate the original goal of promoting low-carbon practices. Therefore, it is crucial to establish a sustainable battery-recycling and disposal system. This study uniquely incorporates the concept of battery echelon utilization into its analytical framework using a Stackelberg game model, exploring the equilibrium strategies for stakeholders in a closed-loop supply chain under carbon emission constraints. We analyzed the impact of multiple factors in the recycling process, as well as the influence of digital technology, on enterprise pricing, recycling efficiency, and the choice of recycling channels. The study found that the market pricing of batteries and electric vehicles is not influenced by recycling participants, but is instead related to the application of digital technology. Numerical simulations further reveal that the battery’s echelon utilization rate and carbon emission limit policies jointly motivate enterprises to be more proactive in recycling. In the joint recycling model, battery suppliers can achieve more substantial profit growth compared to electric vehicle manufacturers, providing new insights and directions for innovation and the development of collaborative models within the supply chain.

Key capabilities for closed-loop supply chain: Empirical evidence from manufacturing firms

The objective of this paper is to explore the capabilities to implement closed-loop supply chain (CLSC). In this regard, a theoretical model grounded in natural resource-based view is proposed, which depicts inter-relationships among the capabilities and CLSC. The model is tested using survey data from Indian manufacturing firms by partial least squares (PLS) approach. The findings show information technology and organizational learning as important lower-order capabilities, and internal integration, demand management and product design as significant higher-order capabilities for CLSC implementation. To the best of authors' knowledge, this is the first study to examine key capabilities for CLSC. The study contributes to CLSC literature by providing an integrative framework, classifying capabilities into lower-order capabilities and higher-order capabilities, and empirically examining the key capabilities for CLSC. The findings provide managers with insights about the hierarchical levels of capabilities for CLSC, which will help them to accordingly deploy the appropriate resources to build capabilities for CLSC.

Optimal Decisions in an Authorized Remanufacturing Closed-Loop Supply Chain under Dual-Fairness Concerns

This paper studies optimal decisions in an authorized remanufacturing closed-loop supply chain (CLSC) consisting of a manufacturer, a retailer, and an authorized third-party remanufacturer with dual-fairness concerns (distributional fairness concerns and peer-induced fairness concerns). Four Stackelberg game models were developed: (i) the dual-fairness concerns are considered by a retailer (model F); (ii) the retailer does not consider both types of fairness concerns (model N); (iii) the retailer only considers the distributional fairness concerns (model D); (iv) the retailer only considers the peer-induced fairness concerns (model P). We use numerical analysis to examine the equilibrium outcomes under dual-fairness concerns. The results show that: (1) The increase in the coefficient of peer-induced fairness concerns will result in more profit for the manufacturer in most cases, while distributional fairness concerns always hurt the manufacturer; (2) In most parameter cases, the increase in the degree of distributional fairness concerns favors the retailer. The retailer considers only peer-induced fairness concerns when the degree of distributional fairness concerns is low and the degree of peer-induced fairness concerns is relatively high, whereas in other cases, two kinds of fairness concerns are ignored; (3) Model P is the most profitable and model D is most disadvantageous for the third party, however, for the manufacturer it is the opposite; (4) The impact of fairness concerns on the environment depends on the retailer’s attitude towards fairness concerns. Model P is better for the environment, while model D has the highest environmental impact. This study introduces dual-fairness concerns into the authorized remanufacturing CLSC model and provides theoretical references for authorized remanufacturing and sustainability practices.

A closed-loop supply chain inventory model with stochastic demand, exchange rate, green investment, and carbon tax

In this paper, a mathematical inventory model for a closed-loop supply chain consisting of a single manufacturer and a single retailer is investigated under a stochastic environment and imperfect production. The manufacturer adopts a remanufacturing policy to recover returned products from the market. The model takes into account exchange rate disparities because the supply chain’s participants are in separate countries. The model also considers carbon emissions, which are expected to be produced from storage, transportation, and production. A carbon policy, namely carbon tax, is implemented to manage the overall emissions resulting from the supply chain. To cope with carbon restrictions, the manufacturer has an opportunity to invest in green technologies. The objective of the study is to find optimal shipment quantity, number of deliveries, safety factor, and green investment such that the joint total cost is minimized. An iterative procedure is suggested to solve the proposed problem, and a numerical example is presented for model validation. The findings imply that variations in the production rate and carbon tax have a significant influence on the model’s performance. Aside from that, the results reveal that uncertainty in the exchange rate and production flaws are important factors that must be considered by managers in making inventory decisions, especially those related to the number of deliveries, frequency of deliveries, and the amount of money invested in green technology. Finally, a sensitivity analysis is provided to explain the behavior of the model.

What is the role of product services in the dual-channel closed-loop supply chain?

With the continuous development of internet technology and increasing awareness of environmental protection among consumers, the dual-channel closed-loop supply chain management combining online direct sales channel and retail channel has received more and more attention, however, the existing research has neglected the service research, so this paper focuses on the service strategy in the dual-channel closed-loop supply chain. In this paper, we propose three service strategy models for dual-channel closed-loop supply chains, including when there is no service provision, after-sales service and recycling service provided by retailers and after-sales service provided by manufacturers and recycling service provided by retailers, compare and analyze the optimal decisions of supply chain members under the three service strategy models, discuss the role of service generated in dual-channel closed-loop supply chains, and propose a service cost-sharing strategy to achieve a Pareto improvement in the effectiveness of a dual-channel closed-loop supply chain. The study finds that service plays a positive role in the dual-channel closed-loop supply chain; the model of manufacturer providing after-sales service and retailer providing recycling service is the best service strategy choice in terms of economic and social benefits; the service cooperation mechanism of service cost sharing can achieve Pareto improvement of the supply chain within a reasonable range.

A waste reduction strategy through autonomation under a closed-loop supply chain management

Currently, apart from manufacturing processes, the remanufacturing of products is considerably important. Appropriate remanufacturing requires the operation of long-run manufacturing systems. However, in long-run processes, the production system may convert to an out-of-control state due to machine breakdowns. Then, defective products are frequently produced; this increases wastage and disrupts environmental sustainability. In this model, a smart autonomation policy is deliberated for an error-free inspection in separating defective products during production. The autonomation policy facilitates waste reduction through remanufacturing. This paper concentrates on customer awareness and service-dependent demand, which directly improves the overall profitability of the system. A discrete investment to reduce setup cost, continuous investment to collect used goods, and cap-and-trade strategy to limit carbon emission are considered to obtain a more realistic model. Classical optimization method is applied for global maximum profit test of the profit function with respect to cycle length, customer awareness, service investment, discrete investment to reduce setup cost, number of shipments, and container capacities. Numerical testing, sensitivity to total profit in different cost parameters, and comparisons with previous research are explained. Some special scenarios including graphical representations are discussed to prove that a large investment is more beneficial than the cost of specific setup and collection.

Closed-loop supply chain network of end-of-life wind turbines mathematical model proposal considering environmental, employment, and cost reduction aspects

The worldwide climate issue makes wind energy an attractive renewable energy source. Wind energy reduces carbon emissions, energy prices, creates jobs, improves power access, and ensures energy security. The mass of employed materials in wind turbines indicates a lot of potential raw materials when the whole mass is evaluated. Additionally, a new wind turbine costs $2–$4 million. Remanufacturing or using recycled raw materials from end-of-life wind turbines is practical due to the decreased cost of new wind turbines. To ensure sustainability, CO2 emissions and social advantages like employment must be considered. Given the typical life expectancy of wind turbines at 20–25 years, this issue must be addressed globally in the mid-term. The objective of the conducted study is to provide a multi-objective mathematical framework that encompasses the environmental, social, and economic aspects of wind turbines at the end of their operational lifespan. Hence, this study presents a methodical framework for achieving sustainability in the wind energy sector through the implementation of a closed-loop supply chain. Furthermore, a lexicographic solution approach is offered for each objective of the mathematical model, with the aim of providing decision makers with a comprehensive overview of solutions. The methodology employed in this work involves the utilization of a mixed-integer linear programming (MILP) approach to address the closed-loop supply chain for end-of-life wind turbines. Additionally, a lexicographic solution approach is provided to effectively solve the problem at hand. The novelty of this article lies in its examination of the closed loop supply chain network for end-of-life wind turbines, encompassing the social, environmental, and economic dimensions. This study represents the first of its kind to explore these aspects comprehensively. The proposed mathematical model has three objectives which cover the remanufacturing and recycling and aims to minimize CO2 emissions, unemployment, and transportation cost. In order to evaluate the proposed model, Türkiye is utilized as case with real-life data and Gurobi 9.1.2 is utilized. The locations of wind turbines could not be collected individually, and Euclidian distance was used instead of road distance due to a lack of data. These are the main limitations of the proposed study. The study revealed that the TEC and TCE lexicographic approach has the best recycling and remanufacturing cost-to-manufacturing cost ratio, 52.54 %. The least desired result is 74.50 % from CTE.